Display device and sensor

ABSTRACT

According to one embodiment, a display device includes a display panel which displays an image, a touch panel provided on the display panel and including a sensor area in which a plurality of electrodes for detecting touch operation are provided and a peripheral area provided around the sensor area, a controller which controls the plurality of electrodes, lead lines provided in the peripheral area to connect the electrodes provided in the sensor area to the controller and a conductive layer provided in a region which overlaps at least part of the lead lines.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Applications No. 2016-105033, filed May 26, 2016; andNo. 2016-213185, filed Oct. 31, 2016, the entire contents of all ofwhich are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a display devicecomprising a touch sensor, and a sensor.

BACKGROUND

Personal digital assistants (smartphones, personal assistant devices(PADs), tablet computers, etc.) comprise a display device of liquidcrystal, organic electroluminescence (to be referred to as ELhereinafter) or the like. The display devices used for the personaldigital assistants generally comprise additional functions including asthat of a touch sensor.

The liquid crystal displays with a touch-sensor function, are subjectedto noise immunity test to evaluate the immunity to externalelectromagnetic noise. An example of the noise immunity test is that anoise wave is radiated from an antenna onto a touch operation surface,and the occurrence of an erroneous touch operation (malfunction) due tothe noise wave is checked.

For preventing the occurrence of malfunctions, it is necessary to formthe detection electrode, which detects touch operations, to beinsusceptible to noise waves reaching from outside. Here, shielding thedetection electrode is one method. It entails the limited shieldedregion and the increase in cost for shielding.

SUMMARY

The present disclosure generally relates to a display device.

According to one embodiment, a display device is provided. The displaydevice includes a display panel which displays an image, a touch panelprovided on the display panel and including a sensor area in which aplurality of electrodes for detecting touch operation are provided and aperipheral area provided around the sensor area, a controller whichcontrols the plurality of electrodes, lead lines provided in theperipheral area to connect the electrodes provided in the sensor area tothe controller and a conductive layer provided in a region whichoverlaps at least part of the lead lines.

Additional features and advantages are described herein, and will beapparent from the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section schematically showing a display deviceaccording to the first embodiment.

FIG. 2 is an enlarged view of the region A shown in FIG. 1.

FIG. 3A is a plan view schematically showing a touch panel employed inthe display device shown in FIG. 1.

FIG. 3B is a diagram showing an example of an equivalent circuit of theregion covered by a conductive layer.

FIG. 4A is a perspective view schematically showing the display deviceshown in FIG. 1.

FIG. 4B is a perspective view schematically showing another example ofthe display device shown in FIG. 1.

FIG. 5 is a plan view schematically showing a display device accordingto the second embodiment.

FIG. 6 is a plan view schematically showing a display device accordingto the third embodiment.

FIG. 7 is a plan view schematically showing a display device accordingto the fourth embodiment.

FIG. 8 is an enlarged plan view of a terminal member and a thirdconductive layer shown in FIG. 7.

FIG. 9 is a cross section schematically showing the display device shownin FIG. 7.

FIG. 10A is a plan view schematically showing a display device accordingto the fifth embodiment.

FIG. 10B is a plan view showing another example of the display deviceaccording to the fifth embodiment.

FIG. 11A is a plan view schematically showing a display device accordingto the sixth embodiment.

FIG. 11B is a plan view showing another example of the display deviceaccording to the sixth embodiment.

FIG. 12 is a plan view schematically showing a display device accordingto the seventh embodiment.

FIG. 13A is a cross section schematically showing a display deviceaccording to the eighth embodiment.

FIG. 13B is a cross section showing another example of the displaydevice according to the eighth embodiment.

FIG. 14 is a plan view schematically showing a mutual-capacitive touchdetection device applied to the display devices according to the firstto eighth embodiments.

FIG. 15 is a plan view schematically showing a self-capacitive touchdetection device applied to the display devices according to the firstto eighth embodiments.

FIG. 16A is a diagram showing the details of the touch detection deviceshown in FIG. 15.

FIG. 16B is a timing chart of the touch detection device shown in FIG.16A.

DETAILED DESCRIPTION

In general, according to one embodiment, a display device comprises: adisplay panel which displays an image; a touch panel provided on thedisplay panel and including a sensor area in which a plurality ofelectrodes for detecting touch operation are provided and a peripheralarea provided around the sensor area; a controller which controls theplurality of electrodes; lead lines provided in the peripheral area toconnect the electrodes provided in the sensor area to the controller;and a conductive layer provided in a region which overlaps at least partof the lead lines.

According to another embodiment, a sensor comprises: a substrateincluding a sensor area and a peripheral area surrounding the sensorarea; an electrode provided in the sensor area so as to detect a touchoperation; a controller which controls the electrode; a terminal memberprovided in the peripheral area so as to connect the electrode and thecontroller to each other; and a first conductive layer located betweenan end of the substrate and the terminal member, the first conductivelayer being at a reference potential and in contact with the substrate.

According to yet another embodiment, a sensor comprises: a substratecomprising a main surface including a sensor area and a peripheral areasurrounding the sensor area, and a side surface; an electrode providedin the sensor area, to detect a touch operation; a controller whichcontrols the electrode; a terminal member provided in the peripheralarea, to connect the electrode to the controller; and a first conductivelayer which is at a reference potential and in contact with the sidesurface.

Embodiments will be described hereinafter with reference to theaccompanying drawings. Incidentally, the disclosure is merely anexample, and proper changes within the spirit of the invention, whichare easily conceivable by a skilled person, are included in the scope ofthe invention as a matter of course. In addition, in some cases, inorder to make the description clearer, the widths, thicknesses, shapes,etc. of the respective parts are schematically illustrated in thedrawings, compared to the actual modes. However, the schematicillustration is merely an example, and adds no restrictions to theinterpretation of the invention. Besides, in the specification anddrawings, the structural elements having functions, which are identicalor similar to the functions of the structural elements described inconnection with preceding drawings, are denoted by like referencenumerals, and an overlapping detailed description is omitted unlessotherwise necessary.

First Embodiment

This embodiment describes a display device with a touch detectionfunction. This embodiment is applicable to any of the devices whichadopt the liquid crystal or a light emitting device such as an organicEL device, as the display element. Further, this embodiment isapplicable to the devices which use an exclusive touch panel independentfrom the display panel, or which share some parts with the parts of thedisplay panel, etc.

FIG. 1 is a cross section schematically showing a display deviceaccording to this embodiment. This embodiment is directed to a liquidcrystal display 100, and will be described with generally adopteddefinitions of the lateral direction in plan view being the firstdirection X, the longitudinal direction being the second direction Y andthe thickness direction being the third direction Z. Further, the screenside, that is, the third direction Z side, is defined as an upper side(surface side), and the opposite side to the screen is defined as alower side (rear side).

The liquid crystal display 100 comprises an active-matrix liquid crystaldisplay panel LCD, a backlight unit BL, a touch panel 13, a controlboard 11, a shield case 12, etc.

The liquid crystal display panel LCD has, for example, a rectangularshape in plan view, and comprises a transmissive display function whichdisplays images by selectively transmitting the light irradiated fromthe backlight unit BL. Note that the liquid crystal display panel LCDmay be of a type which comprise, in addition to the transmissive displayfunction, a reflective display function which displays images byselectively reflecting external light.

The liquid crystal display panel LCD comprises a first substrate SUB1,an opposing second substrate SUB2 and a liquid crystal layer interposedbetween the first substrate SUB1 and the second substrate SUB2. Thefirst substrate SUB1 and second substrate SUB2 are formed from atransparent insulating substrate of, for example, glass or resin.

The backlight unit BL is provided to oppose a lower surface of theliquid crystal display panel LCD. The backlight unit BL may be any ofthe existing various types. For example, one type for the backlight unitBL is a unit in which light-emitting devices are arranged on an edge ofa light guide plate, or another type is a unit in which a cold cathoderay tube is arranged on a rear side of a glass plate which scatterslight.

The control board 11 is provided on a lower surface side of thebacklight unit BL. On the control board 11, mounted are an LCD-controlIC chip which controls the liquid crystal display panel LCD, atouch-panel driving IC chip which drives the touch detection device,which will be explained later, in collaboration with the LCD-control ICchip, etc. Further, mounted thereon are a communication module forcommunicating with outside and a host device on which various types ofapplications are implemented to control the operation of the liquidcrystal display.

The control board 11 is covered with the shield case (or film-likeshield cover) 12 formed from, for example, a metal material to avoidexternal interference with the operation thereof.

The touch panel 13, which constitutes the touch detection device, isprovided on an upper surface (that is, an opposite side to the backlightunit BL) of the liquid crystal display panel LCD. The touch panel 13contains a transparent synthetic resin or glass substrate, and comprisesat least the detection electrode, as will be describe later.

The touch panel 13 and the control board 11 are connected to each otherby a flexible printed circuit substrate 22 for touch panel (, which willbe referred to as FPC hereinafter). Note that the above-describedtouch-panel driving IC chip may be mounted on the touch-panel FPC 22.The liquid crystal display panel LCD and the control board 11 areconnected to each other by a display-panel FPC 21 (including chip-onfilm (COF)).

FIG. 2 is an enlarged view of the region A encircled with the dashedline in FIG. 1. The region A is a part of the edge of the touch panel 13along the second direction Y and indicating mainly the state where aflat surface opposite to the touch operation surface is sectioned alongthe third direction Z. In the flat surface, lead lines LTx connected todrive electrodes, which will be described later, and lead lines LRxconnected to detection electrodes are located.

At least part of these lead lines LTx and LRx is covered with aconductive layer CS for rejecting noise. The surfaces of the lead linesLTx and LRx are coated with an insulation material 15, and therefore thelines are not electrically connected to the conductive layer CS. Theconductive layer CS is, for example, a sheet-like member of a metalmaterial such as copper or aluminum. The conductive layer CS maycomprise, for example, a surface having adhesive property, or it may beadhered to the insulation material 15 with adhesive. Or, the conductivelayer CS may be formed, for example, by applying a pasty conductivematerial containing a metal material such as silver. In this case, theinsulation material 15 may be coated directly with the conductivematerial or a member coated with the conductive material may be arrangedto overlap with the lead lines LTx and LRx.

Between the conductive layer CS and the shield case 12, a gasket 14 isprovided as a shock-absorbing material. The shield case 12 includes anedge a part of which is bent into a bent piece 12 a parallel to thetouch panel 13. The gasket 14 is sandwiched between the bent piece 12 aand the conductive layer CS.

In an area on the opposite surface to the touch operation surface of thetouch panel 13, and also surrounded by the shield case 12, a terminalmember 22 a is provided for connecting the touch-panel FPC 22.

FIG. 3A is a plan view showing an example of arrangement of thedetection electrodes Rx and the drive electrodes Tx provided in thetouch panel 13 and an example of the attachment position of theconductive layer CS as seen from an opposite side to the touch operationsurface (that is, the liquid crystal display panel LCD side). The touchpanel 13 comprises, for detecting touch operations, a plurality of driveelectrodes Tx (Tx1, Tx2, . . . , Txm) and a plurality of detectionelectrodes Rx (Rx1, Rx2, . . . , Rxn) insulated from these driveelectrodes Tx and arranged to cross them in a sensor area SA. Thedetection electrodes Rx (Rx1, Rx2, . . . , Rxn) each extending along thefirst direction X in the sensor area SA are arranged in parallel to eachother along the second direction Y with a gap between each adjacentpair. The drive electrodes Tx (Tx1, Tx2, . . . , Txm) each extendingalong the second direction Y are arranged in parallel to each otheralong the first direction X with a gap between each adjacent pair. Ateach of the crossing portions between the drive electrodes Tx and therespective detection electrodes Rx, a capacitance is formed between eachrespective pair of electrodes crossing each other.

A peripheral area CA is provided around the sensor area SA to surroundit. In the peripheral area CA, the lead lines LTx connected respectivelyto the drive electrodes Tx and the lead lines LRx connected respectivelyto the detection electrodes Rx are arranged. The drive electrodes Tx ofeach column form a loop by the respective lead lines LTx. Morespecifically, along the first direction X, the lead lines LTx of thedrive electrodes Tx in a left half region of the touch panel 13 form aloop through a left edge region of the touch panel 13. The lead linesLTx of the drive electrodes Tx in a right half region of the touch panel13 form a loop through a right edge region of the touch panel 13. Thelead lines LRx of the detection electrodes Rx of each row form a loopthrough an edge region of the touch panel 13 along the second directionY, that is, an edge region on an end portion 13E side parallel to thefirst direction X.

The above-described arrangement is only an example and the shape or thepatterns of the drive electrodes Tx and the detection electrodes Rx arenot necessarily limited to those shown in the figure. In theabove-provided descriptions, the lead lines LTx and LRx form loops, butit is not necessarily so. For example, it suffices if the driveelectrodes Tx and the detection electrodes Rx are formed to be coupledto a touch-panel driving IC chip 23 through the touch-panel FPC 22.

The touch-panel FPC 22 is located on the end portion 13E side andconnected to the terminal member 22 a. The terminal member 22 a is aline-integrated portion for connecting the lead lines LTx and LRx to theoutside. The lead lines LTx and LRx connected to the terminal member 22a are coupled to the touch-panel driving IC chip 23 provided in thecontrol board 11 through the touch-panel FPC 22. The location of theterminal member 22 a is not necessarily limited to within the loop oflead lines shown in the figure. More specifically, for example, theterminal member 22 a may be located on the end portion 13E side.

In the vicinity of the region where the touch-panel FPC 22 is connected,the display-panel FPC (including COF) 21 is also provided. Morespecifically, the display-panel FPC (including COF) 21 is connected tothe liquid crystal display panel LCD on the same side as the touch-panelFPC 22 along the second direction Y. On the display-panel FPC (includingCOF) 21, provided are a drive signal line for driving the liquid crystaldisplay panel LCD, a plurality of video signal lines SL (only onerepresentative signal line is shown) for supplying video signals to theliquid crystal display panel LCD, a control signal line for controllingswitching of signals or switches, etc. These video signal lines SL, etc.are coupled to the LCD-control IC chip (not shown) provided in thecontrol board 11 through the display-panel FPC (including COF) 21.

Here, a plurality of conductive layers CS, namely, a first conductivelayer CS 1 and a second conductive layer CS2 are provided on the endportion 13E side, in a region which partially covers the lead lines LTxand LRx. The first conductive layer CS1 and the second conductive layerCS2 are provided to be apart from each other along the first direction Xso as to partially overlap the lead lines LTx and LRx provided along thefirst direction X in the vicinity of the terminal member 22 a. Note thatit suffices if the first conductive layer CS1 and the second conductivelayer CS2 are provided in the region overlapping at least the lead linesLRx. Moreover, there may be one conductive layer CS or may be three ormore.

The potentials of the first conductive layer CS1 and the secondconductive layer CS2 are fixed to a reference potential, for example,the ground potential. That is, the first conductive layer CS1 and secondconductive layer CS2 are electrically connected to a member (, which maybe called a reference potential member hereinafter) whose potential isfixed to a reference potential such as the ground potential. In thisembodiment, for example, the housing which constitutes the backlightunit BL or the shield case 12 functions as the reference potentialmember as will be described later, and therefore the first conductivelayer CS1 and the second conductive layer CS2 are directly or indirectlyconnected to the housing or the shield case 12.

FIG. 3B shows an example of the equivalent circuit of the region coveredby the conductive layer CS. Note that FIG. 3B shows the representativeequivalent circuit formed from the lead lines LRx and conductive layerCS, but similar equivalent circuits can be represented for the leadlines LTx and conductive layer CS, and the video signal lines SL andconductive layer CS.

The lead lines LRx have a certain resistance. When the conductive layerCS fixed to the reference potential (for example, the ground potential)is provided in the region overlapping the lead lines LRx, a couplingcapacitance C1 is created between each of the lead lines LRx and theconductive layer CS. Here, the coupling capacitance C1 and theresistance of the respective lead line LRx (and the detection electrodeRx) function as a filter to reduce the noise in the value of the currentflowing through the detection electrode Rx. That is, the noise currentflowing through the detection electrode Rx is directed to the terminalconnected to the ground potential through the coupling capacitance C1.

FIG. 4A is a perspective view schematically showing an appearance of theliquid crystal display 100 according to this embodiment. FIG. 4A showsan opposite side to the touch operation surface of the liquid crystaldisplay 100.

The first conductive layer CS1 and the second conductive layer CS2 areelectrically connected to a housing CHS constituting the backlight unitBL. In the example shown in FIG. 4A, the first conductive layer CS1 andthe second conductive layer CS2 are in contact with the housing CHS.Further, the shield case 12 is fixed to the housing CHS with a screw 16.Thus, the shield case 12 can be equalized in terms of potential to thehousing CHS. The housing CHS is coupled to a reference potential (groundpotential) member 18. In the example shown in FIG. 4A, the housing CHSis electrically connected to the reference potential member 18 through ascrew (fixing member) 17 or a conductive member 17 a. In the case wherethe display device is of some other type, the first conductive layer CS1and the second conductive layer CS2 may be connected to the referencepotential member 18 not limitedly thought the backlight unit BL butthrough a conductive member 17 b.

Moreover, as shown in FIG. 4B, the housing CHS need not be fixed to thereference potential member 18 with the screw 17 mentioned above. In thiscase, the housing CHS is capacitively coupled with the referencepotential member 18.

This embodiment is described as an example on the assumption case wherethe display device of a type comprising a transmissive display functionor a reflective display function. When the display device is areflective liquid crystal display or an organic EL display including anorganic EL device, the backlight unit BL can be omitted. In this case,for example, by connecting the housing of the shield case 12 or the liketo the reference potential member with a fixed member or capacitivecoupling and connecting the conductive layer CS to the housing, thisembodiment can be applied also to the reflective liquid crystal displayor the organic EL display.

According to this embodiment, in the peripheral area CA where the leadlines LTx and LRx are formed, the conductive layer CS of a conductivematerial is provided in the region which at least partially overlaps thelead lines LTx and LRx near the touch-panel FPC 22. Thus, even if noiseis created due to, for example, the the adverse effect ofelectromagnetic waves and the like in the lead lines LTx and LRx, it ispossible to reduce the noise entering the touch-panel FPC 22 in theperipheral area CA of the touch panel 13. In other words, the noisewhich enters the touch-panel driving IC chip 23 provided in the controlboard 11 through touch-panel FPC 22 can be reduced. Therefore, itbecomes possible to suppress the malfunction of the touch panel 13.

Moreover, according to this embodiment, the structure can be simplifiedto be able to reduce the production cost, and further the adverse effectof noise can be effectively reduced as compared to the case where thecover made from a conductive material is provided in the entire regionof the touch panel 13.

Furthermore, as can be seen in FIG. 3A, the conductive layers CS areprovided also in the regions which overlap the display-panel FPC(including COF) 21 connected to the LCD-control IC chip. Thus, theadverse effect of the noise created onto the video signal lines SL canalso be reduced. Therefore, for example, screen flicker, which may becaused by the noise, can be suppressed, thereby improving the displayquality. Note that the lead lines LRx and/or LRx extend electrically tobe located on the touch-panel FPC 22, the conductive layer CS isprovided to partially overlap the lead lines LRx and/or LRx located onthe touch-panel FPC 22. The conductive layer CS functions to prevent themalfunction of the touch panel 13 and noise contamination to videosignals, and thus it is utilized effectively at low cost.

Second Embodiment

FIG. 5 is a plan view schematically showing a touch panel 13 used in adisplay device according to the second embodiment. The second embodimentis different from the first embodiment in that a conductive layer CSwhich covers the lead lines LRx and LRx is provided on substantially theentire peripheral area CA. In the illustrated example, the conductivelayer CS is formed to be annular to surround the sensor area SA and theterminal member 22 a.

Note that the annular conductive layer CS need not be formed from asingle member, but from a plurality of members. For example, theconductive layer CS comprises two members extending in the firstdirection X and two members extending in the second direction Y, andthese members may be connected to each other.

In this embodiment also, an advantageous effect similar to that of thefirst embodiment can be obtained. Further, according to this embodiment,the area where the lead lines LRx and LRx and the conductive layer CSoverlap each other is larger; therefore the adverse effect of the noisecreated in the lead lines LRx and LRx can be further reduced.

Third Embodiment

FIG. 6 is a plan view schematically showing a touch panel 13 used in adisplay device according to the third embodiment.

The third embodiment is different from the second embodiment in that aconductive layer CS is not provided between the terminal member 22 a andthe end portion 13E of the touch panel 13. More specifically, theconductive layer CS is formed into substantially a character C shape,which includes a first end portion CSE1 and a second end portion CSE2separated from each other along the first direction X between theterminal member 22 a and the end portion 13E. Note that the conductivelayer CS having such a shape may be formed from a single member or froma plurality of members.

In this embodiment also, an advantageous effect similar to that of thesecond embodiment can be obtained.

Fourth Embodiment

FIG. 7 is a plan view schematically showing a touch panel 13 used in adisplay device according to the fourth embodiment. The fourth embodimentis different from the first embodiment in that a third conductive layerCS3 is provided between the terminal member 22 a and the end portion 13Eof the touch panel 13.

The third conductive layer CS3 is formed into a belt-like shape toextend along the first direction X. The potential of the thirdconductive layer is a reference potential (ground potential). In theillustrated example, the third conductive layer CS3 is closer to the endportion 13E than the terminal member 22 a and does not overlap the leadlines LTx and LRx. But the third conductive layer CS3 may be closer tothe terminal member 22 a than the end portion 13E and may overlap thelead lines LTx and LRx. Moreover, in the illustrated example, one thirdconductive layer CS3 is located between the terminal member 22 a and theend portion 13E, but a plurality of them may be provided. Further, theshape of the third conductive layer CS3 is not limited to a straightline along the first direction X, but may be some other shape such aswavy. The third conductive layer CS3 may be formed from the samematerial as that of the first conductive layer CS1, the secondconductive layer CS2, and conductive layer CS discussed in the first tothird embodiments, or may be formed from a different material.

As shown in FIG. 8, the terminal member 22 a comprises a plurality ofterminals 22 b ( . . . 22 b 1, 22 b 2, 22 bi) arranged along the firstdirection X. In this embodiment, a width H22 of the terminal member 22 aalong the first direction X is defined as the distance between terminals22 b located at both ends of the terminal member 22 a along the firstdirection X. That is, a terminal 22 b 1 located at one end of theterminal member 22 a comprises one end portion (side) S1, and a terminal22 bi located at the other end of the terminal member 22 a comprisesanother end portion (side) S2. The width H22 is equivalent to thedistance between the one end portion (side) S1 and the other end portion(side) S2 along the first direction X.

A width HC of the third conductive layer CS3 along the first direction Xis greater than the width H22. Further, the third conductive layer CS3is formed to be located between each of the terminals 22 b and the endportion 13E. In the illustrated example, the terminals 22 b arerectangular, but may be some other shape. In this case as well, thewidth H22 of the terminal member 22 a along the first direction X issimilarly defined. Further, the plurality of terminals 22 b need not bearranged in line, but may be arranged in staggered fashion. Or theterminal member 22 a may comprise a plurality of terminals 22 b whosedistances from the end portion 13E differ from one another.

FIG. 9 is a cross section of the touch panel 13 taken along line IX-IX′shown in FIG. 7.

The touch panel 13 is formed from a transparent substrate SUB of a resinor glass. The substrate SUB comprises a first main surface 13A on whicha detection electrode Rxn, a drive electrode Tx (not shown) and aterminal member 22 a are provided, a second main surface 13B as a touchoperation surface on an opposite side to the first main surface 13A, anda side surface 13C which meets the first main surface 13A and the secondmain surface 13B.

In this embodiment, the end portion 13E of the touch panel 13corresponds to the region surrounded with the dashed line in FIG. 9.More specifically, the end portion 13E is a region including the firstmain surface 13A, the second main surface 13B and the side surface 13Cof the substrate SUB on the end on the second direction Y side. Thethird conductive layer CS3 is at the reference potential (groundpotential) and is in contact with the main surface 13A between the endportion 13E and the terminal member 21 a. The connection relationshipbetween the third conductive layer CS3 and the reference potentialmember is the same as that of the example shown in FIGS. 4A and 4B.Further, the third conductive layer CS3 may extend to the end portion13E, as will be described later.

In the illustrated example, the side surface 13C is a plane parallel toa X-Z plane defined by the first direction X and the third direction Z,but is not limited to this. For example, the side surface 13C may be aplane inclined with respect to the third direction Z, or a curvedsurface, or it may include a planar section and a curved section.Further, the touch panel 13 may include a protection film and the like,provided on, for example, a main surface 13A side in addition to thesubstrate SUB, the detection electrode Rx, the drive electrode Tx andthe like.

According to the fourth embodiment, the third conductive layer CS3 isprovided between the terminal member 22 a and the end portion 13E on theterminal member 22 a side. With this structure, it is possible tosuppress the noise from propagating the creepage surface of the touchpanel 13 and entering the terminal member 22 a.

For example, as shown in FIG. 9, when static discharge occurs on thesecond main surface 13B, which is a touch operation surface, the noisecurrent caused by the static discharge may sneak into the first mainsurface 13A through the end portion 13E of the touch panel 13. In otherwords, the noise current created in the second main surface 13B maypropagate through the second main surface 13B, the side surface 13C andthe first main surface 13A, to reach the terminal member 22 a. Accordingto this embodiment, the third conductive layer CS3 at the groundpotential is in contact with the first main surface 13A between theterminal member 22 a and the end portion 13E, and therefore the noisecurrent propagating from the second main surface 13B through the endportion 13E and sneaking into the first main surface 13A is absorbed bythe third conductive layer CS3 before entering the terminal member 22 a.

Meanwhile, the size of the noise current propagating through thecreepage surface of the touch panel 13 becomes smaller as the distanceto propagate becomes larger. According to this embodiment, as shown inFIG. 8, the width HC of the third conductive layer CS3 is greater thanthe width H22 of the terminal member 22 a. With this structure, forexample, when the noise current propagating from the second main surface13B through the end portion 13E and having reached the first mainsurface 13A detours both ends of the third conductive layer CS3 alongthe first direction X, the distance for the noise current to propagatethrough to the terminal member 22 a is sufficiently large. In otherwords, the size of the noise current propagating from the second mainsurface 13B is sufficiently reduced by the time it reaches the terminalmember 22 a. Thus, according to this embodiment, it is possible tosuppress noise current from entering the terminal member 22 a.

Fifth Embodiment

FIGS. 10A and 10B are plan views each schematically showing a touchpanel 13 used in a display device according to the fifth embodiment. Thefifth embodiment is different from the fourth embodiment in that thetouch panel 13 further comprises a first conductive layer CS1 and asecond conductive layer CS2 described in the first embodiment inaddition to the third conductive layer CS3.

In the example shown in FIG. 10A, the third conductive layer CS3 islocated closer to the end portion 13E than the first conductive layerCS1 and the second conductive layer CS2, and in the example shown inFIG. 10B, the third conductive layer CS3 is closer to the terminalmember 22 a than the first conductive layer CS1 and the secondconductive layer CS2.

In this embodiment, the first conductive layer CS1, the secondconductive layer CS2 and the third conductive layer CS3 are separatedfrom each other, but are set to the same potential, for example, areference potential (ground potential). A width HC of the thirdconductive layer CS3 along the first direction X is greater than adistance D1 between the first conductive layer CS1 and the secondconductive layer CS2 along the first direction X. In the example shownin FIG. 10A, the third conductive layer CS3 is located between the firstconductive layer CS1 and the end portion 13E and also between the secondconductive layer CS2 and the end portion 13E. In the example shown inFIG. 10B, the first conductive layer CS1 and the second conductive layerCS2 are located between the third conductive layer CS3 and the endportion 13E.

According to this embodiment, it is possible to reduce the adverseeffect of the noise current created in the lead lines LTx and LRx whilesuppressing the entering of the noise current to the terminal member 22a.

Sixth Embodiment

FIGS. 11A and 11B are plan views each schematically showing a touchpanel 13 used in a display device according to the sixth embodiment. Thesixth embodiment is different from the fifth embodiment in that thethird conductive layer CS3 is connected to the first conductive layerCS1 and the second conductive layer CS2.

The third conductive layer CS3 is connected to the first conductivelayer CS1 and the second conductive layer CS2 with an adhesive havingconductivity as shown in FIG. 11A. Or, as shown in FIG. 11B, the firstconductive layer CS1, the second conductive layer CS2 and the thirdconductive layer CS3 may be formed to be integrated as one. In otherwords, a conductive layer CS of a single member which overlaps the leadlines LTx and LRx and is in contact with the touch panel 13 may beprovided between the terminal member 22 a and the end portion 13E. Inaddition, the third conductive layer CS3 may be connected to the firstconductive layer CS1 and the second conductive layer CS2 on a side ofthe terminal member 22 a.

In this embodiment also, an advantageous effect similar to that of thefifth embodiment can be obtained. Further, when the first conductivelayer CS1 and the second conductive layer CS2 are in contact with thetouch panel 13, there is no transmitting path for noise current betweenthe first conductive layer CS1, the second conductive layer CS2 and thethird conductive layer CS3; therefore it becomes possible to furthersuppress the entering of the noise current to the terminal member 22 a.

Seventh Embodiment

FIG. 12 is a plan view schematically showing a touch panel 13 used in adisplay device according to the seventh embodiment. The seventhembodiment comprises a conductive layer CS described in the thirdembodiment and a third conductive layer CS3 described in the fourthembodiment.

In the illustrated example, the third conductive layer CS3 is locatedcloser to the end portion 13E than the conductive layer CS along thesecond direction Y, but it may be located between a first end portionCSE1 and a second end portion CSE2 of the conductive layer CS and theterminal member 22 a. A width HC of the third conductive layer CS3 alongthe first direction X is greater than a distance D2 between the firstend portion CSE1 and the second end portion CSE2 of the conductive layerCS along the first direction X.

In this embodiment also, an advantageous effect similar to that of thefifth embodiment can be obtained. Note that FIG. 5 illustrated for thesecond embodiment is equivalent to the state where the third conductivelayer CS3 and the conductive layer CS of this embodiment are connectedto each other. Therefore, with the conductive layer CS shown in FIG. 5as well, it is possible to reduce the adverse effect of the noisecurrent created in the lead lines LTx and LRx and suppress the noisecurrent propagating the creepage surface of the touch panel 13 andentering the terminal member 22 a.

Eighth Embodiment

FIGS. 13A and 13B are cross sections of a touch panel 13 used in adisplay device according to the eighth embodiment. The eighth embodimentis different from the fourth to seventh embodiments in that a thirdconductive layer CS3 is in contact with a side surface 13C of asubstrate SUB. In the example shown in FIG. 13A, the third conductivelayer CS3 is in contact with the side surface 13C only. In the exampleshown in FIG. 13B, the third conductive layer CS3 has covers the endportion 13E. In other words, the third conductive layer CS3 is incontact with the second main surface 13B, the side surface 13C and thefirst main surface 13A. Note that it suffices if the third conductivelayer CS3 is in contact with at least one of the first main surface 13Aand the side surface 13C.

In this embodiment also, an advantageous effect similar to that of thefourth embodiment can be obtained.

Example of Application

The detection mode of the touch detection device (sensor) adopted by anyof the embodiments described above may be any of the mutual capacitancemode (mutual mode) and the self-capacitance mode (self mode).

FIG. 14 shows a basic structure of a touch detection device 200 of themutual capacitance mode. The touch detection device 200 comprises atouch panel 13 and a touch-panel driving IC chip 23 for controlling thetouch panel 13. In the mutual capacitance mode, the substrate SUB of thetouch panel 13 comprises a plurality of drive electrodes Tx (Tx1, Tx2,Tx3, . . . ) and a plurality of detection electrodes Rx (Rx1, Rx2, Rx3,. . . ) arranged to be insulated from and cross these drive electrodesTx, to detect touch operation. The drive electrodes Tx (Tx1, Tx2, Tx3, .. . ), each being elongated along the second direction Y (or a lateraldirection), are arranged in parallel to each other with gapstherebetween along in the first direction X (or a longitudinaldirection). The detection electrodes Rx (Rx1, Rx2, Rx3, . . . ), eachbeing elongated in the first direction X, are arranged in parallel witheach other with gaps therebetween along the second direction Y. In eachof the crossing portions between the drive electrodes Tx and therespective detection electrodes Rx, a capacitance is formed between eachopposing pair of the electrodes.

Note that a common electrode to which a fixed potential is given in thedisplay panel during a displaying period may be used as the driveelectrodes Tx. In other words, in a display device called an incelltype, the drive electrodes Tx (Tx1, Tx2, Tx3, . . . ) are used also as acommon electrode for pixel circuits. In a display device called anon-cell type, the drive electrodes Tx and the detection electrodes Rxare provided as electrodes exclusively used for touch detection for thetouch panel for touch detection (the substrate for touch detection). Thetouch detection device 200 is controlled by the touch-panel driving ICchip 23.

The touch detection period is dispersedly set, for example, in oneframe. Therefore, in the display device, the display period and thetouch detection period are time-divided. A selector SELA suppliespulse-form driving signals Txs to the drive electrodes Tx1, Tx2, Tx3, .. . , sequentially during the touch detection period. If the user'sfinger is contact with (touching) somewhere, the detection signal Rxsoutput from the detection electrode of the touched position is at alevel lower than that of the detection signal Rxs output from the otherdetection electrodes. The example shown in the figure illustrates thecase where the detection signal level when a touch is not detected isAP1, and the case where the detection signal level of the electrodewhich detects a touch is AP2<AP1.

The mutual capacitance mode which utilizes the drive electrodes Tx andthe detection electrodes Rx is described above, but the drive electrodesTx and the detection electrodes Rx may be used as electrodes of theself-capacitance mode. For example, the touch detection device 200 maybe operated as a self-capacitance mode by using the drive electrodes Txonly, or by using the detection electrodes Rx only. Such operation isexecuted, for example, in a power saving state.

FIG. 15 shows a structural example of the touch detection device 200 ofthe self-capacitance mode. The touch detection device 200 comprises atouch panel 13, a touch-panel driving IC chip 23 and a drive-detectcircuit DDET. In the self-capacitance mode, the substrate SUB of thetouch panel 13 comprises a plurality of common electrodes CE (CE11,CE12, CE13, . . . , CE21, CE22, CE23, . . . , CE31, CE32, CE33, . . . )arranged in a matrix to detect touch operation. Lead lines TR (TR1, TR2,. . . ) are connected to the common electrodes CE, respectively. Thelead lines TR are connected to the drive-detect circuit DDET. Thedrive-detect circuit DDET is provided in the non-display area of thefirst substrate (array substrate) SUB1 of the liquid crystal displaypanel LCD, for example. The drive-detect circuit DDET is controlled bythe touch-panel driving IC chip 23 (controller), to control the touchdetection function. Note that the area of one common electrode CE is,for example, about 24 times that of one pixel region.

FIG. 16A shows a plurality of common electrodes CE (CE11, CE21, CE31, .. . ) constituting one column along the second direction Y of the theself-capacitance touch detection device 200 shown in FIG. 15. The commonelectrodes CE are connected to the touch-panel driving IC chip 23through the drive-detect circuit DDET. The drive-detect circuit DDETcomprises a first selector 501 which can select the common voltage Vcom,and a sensing circuit 520. The following description is based on anassumption case where these common electrodes CE include five commonelectrodes CE11, CE21, CE31, CE41 and CE51.

The lead lines TR1 to TR5 are drawn from the common electrodes CE11 toCE51, respectively, to the drive-detect circuit DDET. The drive-detectcircuit DDET comprises the first selector 501 for applying the commonvoltage Vcom to all of the common electrodes CE11 to CE51 during thedisplay period. Further, the lead lines TR1 to TR5 are connected to asecond selector 522 in the sensing circuit 520 through the firstselector 501.

The second selector 522 selects each of the lead lines TR1 to TR5 one byone to supply a sensor signal to each of the lead lines TR1 to TR5. Thesensor signal supply period is the touch detection period shown in FIG.16B. Within one frame, the display period is time-divided and the touchdetection period is set between a display period and another displayperiod.

The sensor signal is generated by a sensor signal generator 524 and isinput to the second selector 522 through a conversion circuit 523.Further, the sensor signal is output as a detection signal also to anoutput side of the conversion circuit 523, that is, a detection circuit530 side. Let us suppose now that the user is touching with a finger oneof the common electrodes CE11 to CE51. Then, when the sensor signal issupplied to the common electrode, the sensor signal output from theconversion circuit 523 is at a level (touch detection level) differentfrom a level (non-detection level) of the case where not touching.

The configuration of the conversion circuit 523 is not particularlylimited, but may be configured, for example, to be connected to aplurality of common electrodes CE for detecting touch operation bycapacitance coupling. In this case, a common electrode CE is driven by asignal of the sensor signal generator 524 through capacitance coupling.Whether there is a touch or not can be detected with the detectioncircuit by measuring the fluctuation voltage level of the commonelectrode CE. When a finger is touching a common electrode CE, thecapacitance component of the common electrode CE is greater as comparedto that when a finger is not touching. Therefore, when a finger istouching, the voltage fluctuation of the common electrode CE becomesless as compared to that when a finger is not touching.

The detection circuit 530 comprises a switch 531, an operationalamplifier 532, a filter 533 and an A/D converter 534. The operationalamplifier 532 may be configured to be able to connect to (during thetouch detection period) and disconnect from (during the display period)the conversion circuit 523 by the switch 531 provided in its perviousstage.

The operational amplifier 532 receives the sensor signal from theconversion circuit 523 and outputs a difference between this signal anda threshold Vref. Further, a capacitor 535 and the switch 536 areconnected in parallel to the operational amplifier 532. The output ofthe operational amplifier 532 is reset by, for example, turning on theswitch 536 during the display period. The switch 531 and the switch 536are switched based on, for example, the control data from thetouch-panel driving IC chip 23.

The value output from the operational amplifier 532 is subjected to thefilter 533 to remove noise therein and then converted to a digitalsignal by the A/D converter 534. This digital value is input to thetouch-panel driving IC chip 23 as touch detection data. The touch-paneldriving IC chip 23 executes arithmetic operation based on the data fromthe sensing circuit 520, and pinpoints the touch position. Thetouch-panel driving IC chip 23 stores sequence control data forcontrolling the first selector 501, the second selector 522, the switch531, etc. Therefore, the touch-panel driving IC chip 23 is able todetect, when touch detection data is input from the detection circuit530, from which common electrode the detection data is output.

In the description provided above, the touch detection operation usingthe common electrodes CE11 to CE51 of the first column is illustrated,but the touch detection operation is executed in a similar methodsequentially onto the common electrodes of the second column, the thirdcolumn and so on as well. In this case, the sensing circuit 520 may beused as a sensing circuit for each column sequentially. Or an exclusivesensing circuit may be provided for each column.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A display device comprises: a display panel whichdisplays an image; a touch panel provided on the display panel andincluding a sensor area in which a plurality of electrodes for detectingtouch operation are provided and a peripheral area provided around thesensor area; a controller which controls the plurality of electrodes;lead lines provided in the peripheral area to connect the electrodesprovided in the sensor area to the controller; and a conductive layeroverlapping the lead lines and surrounding the sensor area, wherein theconductive layer includes a first end and a second end separated fromeach other.
 2. The display device of claim 1, wherein the conductivelayer is connected to a reference potential member.
 3. The displaydevice of claim 2, wherein the reference potential member is a housingprovided to oppose the display panel.
 4. The display device of claim 3,wherein the housing is connected to a reference potential by a fixingmember.
 5. The display device of claim 3, wherein the housing isconnected to a reference potential by capacitance coupling.
 6. Thedisplay device of claim 1, wherein the conductive layer further overlapsa video signal line connected to the display panel.
 7. The displaydevice of claim 1, wherein the lead lines extend electrically on aflexible substrate, and the conductive layer overlaps part of the leadlines, located on the flexible substrate.
 8. The display device of claim1, wherein the electrode is a drive electrode or a detection electrodeprovided in the touch panel.
 9. The display device of claim 1, whereinthe display panel is a display panel adopting liquid crystal or alight-emitting element.
 10. A sensor comprising: a substrate including asensor area and a peripheral area surrounding the sensor area; anelectrode provided in the sensor area so as to detect a touch operation;a controller which controls the electrode; a terminal member provided inthe peripheral area so as to connect the electrode and the controller toeach other; and a first conductive layer located between an end of thesubstrate and the terminal member, the first conductive layer being at areference potential and in contact with the substrate, wherein theterminal member includes a plurality of terminals arranged along a firstdirection, and a width of the first conductive layer along the firstdirection is greater than a distance between a first terminal located onone end of the terminal member and a second terminal located on an otherend thereof along the first direction, the sensor further comprising: alead line provided in the peripheral area so as to connect the electrodeand the terminal member to each other; and a second conductive layer anda third conductive layer separated from each other along the firstdirection between the end and the terminal member, wherein the secondconductive layer and the third conductive layer overlap the lead lineand are at a same potential as that of the first conductive layer. 11.The sensor of claim 10, wherein a width of the first conductive layeralong the first direction is greater than a distance between the secondconductive layer and the third conductive layer along the firstdirection.
 12. The sensor of claim 10, wherein the first conductivelayer is in contact with the second conductive layer and the thirdconductive layer.
 13. A sensor comprising: a substrate including asensor area and a peripheral area surrounding the sensor area; anelectrode provided in the sensor area so as to detect a touch operation;a controller which controls the electrode; a terminal member provided inthe peripheral area so as to connect the electrode and the controller toeach other; and a first conductive layer located between an end of thesubstrate and the terminal member, the first conductive layer being at areference potential and in contact with the substrate, wherein theterminal member includes a plurality of terminals arranged along a firstdirection, and a width of the first conductive layer along the firstdirection is greater than a distance between a first terminal located onone end of the terminal member and a second terminal located on an otherend thereof along the first direction, the sensor further comprising: alead line provided in the peripheral area so as to connect the electrodeto the terminal member; and a second conductive layer overlapping thelead line and surrounding the sensor area, wherein the second conductivelayer includes a first end and a second end separated from each otheralong the first direction between the end and the terminal member. 14.The sensor of claim 13, wherein a width of the first conductive layeralong the first direction is greater than a distance between the firstend and the second end along the first direction.
 15. A sensorcomprising: a substrate comprising a main surface including a sensorarea and a peripheral area surrounding the sensor area, and a sidesurface; an electrode provided in the sensor area, to detect a touchoperation; a controller which controls the electrode; a terminal memberprovided in the peripheral area, to connect the electrode to thecontroller; a first conductive layer which is at a reference potentialand in contact with the side surface; a lead line provided in theperipheral area; and a second conductive layer overlapping the lead lineand surrounding the sensor area, wherein the second conductive layerincludes a first end and a second end separated from each other along afirst direction, and a width of the first conductive layer along thefirst direction is greater than a distance between the first end and thesecond end along the first direction.
 16. The sensor of claim 15,wherein the first conductive layer is in contact with the main surface.